Tubular scaffold



June 17, 1941. B. sci- 2245.939v

TUBULAR ScAFFOLD I Filed Jan. 15, 1940 2 Sheets-Sheet 1 I INVENTOR Patented June 17, 1941 UN l'lE STATES PATENT OFFICE 2 Claims.

My invention relates to scaffolds, particularly to tubular scaffolds-scaifolds consisting in tubular units of steel that are assembled, rigidly united, and braced in knownway.

More particularly, the invention is directed to tubular scalfolds in which the workmens. platforms or catwalks are borne upon spawls, spawls being rigid cantilever beams that extend laterally from the scaffold proper, and support on their extending ends the said platforms or walks. scaffolds of this sort may be found in use at the present time in shipyards and dry docks, and it is in association with such scaffoldsthat I shall describe the invention.

The invention is centered in a structural element for securing the spawls to the tubular legs of the scaffold, and the object-is to provide an element that affords greater security. of assembly; that facilitates the vertical and horizontal adjustments of the spawls; that permits the ready assembly and removal of the spawls; and that withal is of simplified, durable and economical construction. With this in mind, it is to be understood that the invention consists in a clamping device that embodies certain valuable refinements and elaborations in structure and in structural organization.

In the accompanying drawings:

Fig. I is a diagrammatic view, illustrating in broken lines the hull of a boat in a dry-dock, and in full lines a scaffold in which the structural element of this invention finds utility;

Fig. II is a fragmentary view, showing in side elevation and to larger scale two of the vertical legs of the scaffold, and illustrating how each of the cantilever beams or spawls are assembled and secured in the scaffold structure;

Fig. III is a fragmentary View, showing to still larger scale, on the plane of section III-III of Fig. II, one of the spawl-securing elements of the invention;

And Fig. IV is a View of the element as seen on the plane IVIV of Fig. III.

Referring to Fig. I of the drawings two scaffolds or scaffold towers l, I appear in end elevation. They are arranged on opposite sides of the hull 2 of a boat that is undergoing construction or repair. The scaffold structures rest upon the ground or floor 3; they extend lengthwise of the sides of the hull 2, and provide support for platforms or catwalks 4 upon which men may stand while at work on the hull.

More specifically, each scaffold structure includes a succession or line of paired tower legs 5, 5; the line of paired legs extends, as has been already indicated, lengthwise of the side of the hull, and the several pairs of legs are spaced apart horizontally in the line, while the legsof each pair. are spaced .apart transversely of the line, as may be seen in Fig. I. The tower legs are constructed of tubular steel units, erected end on end in known Way, and rigidly united by means of known connecting devices, and the created legs are rig'idly braced both longitudinally and transversely of the assembled structure. (Note the horizontal braces 6 and the diagonal struts l in the drawings.)

The scaffold structure includes means for supporting the platforms 4, and such means consist in horizontal beams 3, which, as already mentioned, are referred to in the art as spawlsf The spawls 8 are carried by the paired tower legs 5, 5, and they arearranged on the successive pairs of legs in horizontal lines, with the effect that each line of spawls provides support for an elongate platform 4. It will be perceived that the spawls extend laterally from the scaffold structure proper, and bear the platforms on their extending ends, in such position that the workmen may stand close to the side of the hull 2 onwhich they are working.

To the end that the platforms 4 may be quickly installed in the scaffold structure, it is essential that the spawls may be readily applied and secured to the paired legs 5, 5. In order that the platforms may be appropriately placed it is necessary that in the assembly they should project different distances from the platform in conformity with the contour of the ships hull. The spawls should, therefore, in assembly extend different distances fromthe scaffold, and it is desirable that this accommodation be made inthe attachment of the spawlsto the scaffold legs.

Referring to Fig. 11, such means consist in a pair of clamping devices 9, 9, one secured upon each of the two scaffold legs 5, 5 that support the particular spawl 8. Each device 9 includes a known form of clamp, consisting in a saddleblock l0 and a girth-member II. The block l0 engages saddle-wise the tubular scaffold leg 5 to which it is applied (Fig. IV), and the girth-member H is adapted to clamp the block upon the scaffold leg. The girth-member is at one end pivoted to the saddle-block, c. f. pin l2, and at its opposite, distal end is adapted to engage such block and clamp it to the scaffold leg. It is characteristic of the structure that the engagement of the distal end of the girth-member with the saddle-block may be readily established and interrupted, as is desirable to permit the device to be quickly applied to and removed from the scafiold leg. More particularly, the distal end of the girth-member H is bifurcated, as at l3, readily to receive the shank of a clamping screw [4, which is articulated at its head-end to the saddle-block, as by means of a pin [5. The distal end of the clamping screw is threaded and carriesa nut l6, and, when the parts have been brought to essembled positions, Figs. III and IV, the nut It; may be run tightly against the bifurcated end of the girth-member, with the manifest efiect that the spawl-securing device is securely clamped to the scaffold leg.

In elaboration of such known form of clamp, the saddle-block I i provided with a stirrupmember 20. The stirrup-member may be riveted, bolted, welded, or otherwise rigidly secured to the saddle-block. In this case it is shown to be cast integrally with the saddle-block, with reinforcing ribs 22 and 23 arranged to strengthen the union of the parts. The saddle-block extends in a horizontal plane and circumferentially of the scafiold leg, while the stirrup-member 20 extends in a vertical plane, parallel with the axis of the scaffold leg. therwise expressed, the stirrup-member extends at an angle of 90 to the saddle-block. The stirrup-member embraces between its legs 2 I, 2 I" the body of the beam or spawl 8, and a clamping bolt 24 extends between and through the legs. It will be noted that the bolt 24 and the stirrupmember completely embrace the body of the spawl-a safety feature of notable value. The legs of the stirrup-member may be minutely flexible, and adapted to yield to the tension of bolt 24, when a nut 25 is tightened thereon, into secure clamping engagement with the body of the spawl.

In order to effect the vertical adjustment of the spawl 8, it ismerely necessary to loosen the nuts I6 of the two spawl-supporting elements or devices 9, 9. This does not operate to disengage the devices from the two scaffold legs, but serves only to loosen saddle-blocks sufficiently to permit them to be slid vertically upon the legs into desired position of vertical adjustment. The nuts l6 are then retightened. temporary loosening of the nuts 25 on the stirrupbolts 24 so far relieves the spawl-clamping engagement of the stirrup-legs 2|, 2| that the spawl may be slid in the stirrups to any desired position of horizontal adjustment. Thus, the desired ends are readily and effectively gained in a structure of simple and economical form.

It may be noted that, by virtue of the spawlembracing form of the stirrup-members 20 and bolts 24, the security of the assembly is not dependent upon a positive clamping action. That is to say, under the effect of the cantilever load imposed upon the projecting ends of the spawls in service (note vertical arrow in Fig. 11), any

Similarly, the i aamee tendency for the spawls to slide horizontally is prevented.

Within the terms and intent of the appended claims, various modifications in structure may be adopted without departure from the invention.

I claim as my invention:

1. In a scafiold including a pair of horizontally spaced-apart vertical legs, a horizontally extending beam, and means for securing said beam to said legs, with the beam extended laterally from the scaffold structure to provide a cantilever support for a workmens platform; the invention herein described in which said means comprise a pair of clamping devices applied one to each of said legs, each of said clamping devices including a saddle member extending circumferentially of the scafiold leg to which the device is applied, a girth member engaging said saddle member and clamping it to the leg to which it is applied, an U- shaped stirrup member integrated at the base of the U to said saddle member,said base of the U extending above and below the plane of said saddle member in a direction normal to such plane, the legs of the U extending horizontally from the base of the U at points spaced severally at an interval above and at an interval below the plane of said saddle member and adapted to engage said beam in an embrace effective and secure against cantilever stresses imposed upon the beam.

2. In a scaffold including a pair of horizontally spaced-apart vertical legs, a horizontally extending beam, and means for securing said beam to said legs, with the beam extended laterally from the scaffold structure to provide a cantilever support for a workmens platform; the invention herein described in which said means comprise a pair of clamping devices applied one to each of said legs, each of said clamping devices including a saddle member extending circumferentially of the scafiold leg to which the device is applied, a girth member engaging said saddle member and clamping it to the leg to which it is applied, an U-shaped stirrup member integrated at the base of the U to said saddle member, said base of the U extending above and below the plane of said saddle member in a direction normal to such plane, the legs of the U extending horizontally from the base of the U at points spaced severally at an interval above and at an interval below the plane of said saddle member and adapted to engag said beam in an embrace effective and secure against cantilever stresses imposed upon the beam, the distal ends of said legs of the U extending laterally from the embraced beam, and a bolt extending between and secured to such projecting ends of the legs and serving with the base of the U and the two legs of the U to complete the embracement of the body of the beam.

MORGAN B. SCHILLER. 

